Ignition security systems for automotive applications may utilize a Hall-effect magnetic sensor in the ignition switch lock assembly to generate a specific voltage code for transmission to a microprocessor of the ignition system of the vehicle. The Hall-effect sensor may be located in the lock sleeve, and is activated by a magnet located in the lock cylinder. The magnet in the lock cylinder provides the magnetic flux necessary to turn on the Hall-effect sensor. During normal operation the magnet is rotated past the Hall-effect sensor, and the output of the Hall-effect sensor changes from a high level to a low level resulting in a set voltage at the output of the Hall-effect sensor. This output is latched and remains low when the magnet is rotated past the Hall-effect sensor and the magnetic field strength has decreased to a level below that which is necessary to turn on the Hall-effect sensor.
External simulations of a magnetic field may result in proper operation of the Hall-effect sensor to generate the required voltage code information to the ignition system microprocessor to thereby defeat the vehicle security system. Therefore, vehicle anti-tampering systems have been developed to make theft of a vehicle more difficult.
A need has thus arisen for an improved security system for a Hall-effect sensor utilized in a vehicle ignition security system.